The impeller is the mechanical energy that is fed by the original motive to the liquid, which increases the core component of the liquid energy. There are open, semi-open and closed impeller. The open impeller has no front and back plates and only leaves, which are used to transport fluid containing impurities. Half open impeller is set only. Closed impeller has a front and back plate. The impeller of centrifugal pump is applied to the impeller.

The impeller should be sufficient strength and stiffness; The flow pattern is the streamline of the fluid flow pattern, the fluid flow velocity is uniform, the channel resistance is as small as possible, and the surface roughness is small. Impeller should have good static balance and dynamic balance; Simple structure, good manufacturing process. Impeller is usually cast.